Image acquisition hardware scanning from Java
Here's an article discussing how to implement your own API using TWAIN (confusingly also called JTwain).
From the article:
Java's lack of a standard image-acquisition API is an oversight that hopefully will be rectified in a future release. Until that time, however, we can either purchase a commercial API or create our own API.
We can base our API on either of the TWAIN or SANE specifications. So far, we've only looked at TWAIN, in terms of the big picture and important details. We have also explored the very simple TWAIN-based JTwain API and played with a simple JTwainDemo application that demonstrates JTwain.
If it's for personal or educational use, maybe you can use Morena: http://www.gnome.sk/Twain/jtp.html
Unfortunetely, if it's for commercial use you will have to pay for it.